Contributions
Abstract: EP344
Type: E-Poster Presentation
Session title: Acute lymphoblastic leukemia - Clinical
Background
Although CD19-specific chimeric antigen receptor (CAR) T-cell therapy has achieved high complete remission rates in relapsed/refractory B-cell lymphoblastic leukemia (r/r B-ALL), some patients relapse after CAR-T. This has become an urgent problem to be solved. CD22 isalso expressed in most cases of B-ALL. We conducted a CD22 CAR T-cell therapy in 19 relapsed orrefractory (r/r) B-ALL adult patients, including 18 patients who failed from previous CD19 CAR T-cell therapy and 1 patient without CD19 CAR T-cell therapy because of lossing CD19 antigen.
Aims
To evaluate the treatment efficacy of CD22 CAR T-cell for adults with refractory or relapsed B acute lymphoblastic leukemia.
Methods
From July 2017 to October 2020, a total of 19 treated adult r/r B-ALL patients were enrolled. The patients were hematological relapse. Eighteen patients had accepted prior CD19 CAR-T therapy, and relapsed with CD22 antigen expression identified by flow cytometer (FCM), 1 case had not a history of CD19 CAR-T therapy because of lossing CD19 antigen. CAR-T cells were produced by lentiviral vectors encoding second generation CARs composed of CD3ζ and 4-1BB. All patients accepted fludarabine and/or cyclophosphamide before infusion. The treatment effect was evaluated on day 30 after cell infusion, MRD was quantified by FCM and PCR for fusion gene. The last follow-up was as of October 24, 2020.
Results
The median age of 19 patients was 30 (range, 18-63) years, including 7 underwent allogeneic transplantation. All patients received ≥1×105 /kg CD22-CAR T cells .Complete remission (CR) or CR with incomplete count recovery (CRi) was achieved in 15 of 19 patients (78.9%) that could be evaluated on day 30 after infusion.Cytokine release syndrome (CRS) occurred in all patients,But most patients only experienced mild cytokine-release syndrome and neurotoxicity.In 15 CR and CRi patients, 8 patients followed by allogeneic hematopoietic cell transplantation after CD22 CAR-T, These patients remained in remission at 4 to 39.7 months after transplantation, another 7 patients did not undergo HCT, 1 relapsed at 1 months,6 of them remained in remission at 4 to 26.5 months after infusion . Among 4 NR patients, 3 died of disease progression, and 1 accepted salvage transplantation who had survived for 4.6 months.
Conclusion
CD22 CAR T-cells was highly effective in inducing remission in adult r/r B-ALL patients,transplantation followed-by CD22-CART allowed CR patients to obtain a remission of 4-39.7months.
Keyword(s): CAR-T, Lymphoplasmacytic lymphoma, Refractory
Abstract: EP344
Type: E-Poster Presentation
Session title: Acute lymphoblastic leukemia - Clinical
Background
Although CD19-specific chimeric antigen receptor (CAR) T-cell therapy has achieved high complete remission rates in relapsed/refractory B-cell lymphoblastic leukemia (r/r B-ALL), some patients relapse after CAR-T. This has become an urgent problem to be solved. CD22 isalso expressed in most cases of B-ALL. We conducted a CD22 CAR T-cell therapy in 19 relapsed orrefractory (r/r) B-ALL adult patients, including 18 patients who failed from previous CD19 CAR T-cell therapy and 1 patient without CD19 CAR T-cell therapy because of lossing CD19 antigen.
Aims
To evaluate the treatment efficacy of CD22 CAR T-cell for adults with refractory or relapsed B acute lymphoblastic leukemia.
Methods
From July 2017 to October 2020, a total of 19 treated adult r/r B-ALL patients were enrolled. The patients were hematological relapse. Eighteen patients had accepted prior CD19 CAR-T therapy, and relapsed with CD22 antigen expression identified by flow cytometer (FCM), 1 case had not a history of CD19 CAR-T therapy because of lossing CD19 antigen. CAR-T cells were produced by lentiviral vectors encoding second generation CARs composed of CD3ζ and 4-1BB. All patients accepted fludarabine and/or cyclophosphamide before infusion. The treatment effect was evaluated on day 30 after cell infusion, MRD was quantified by FCM and PCR for fusion gene. The last follow-up was as of October 24, 2020.
Results
The median age of 19 patients was 30 (range, 18-63) years, including 7 underwent allogeneic transplantation. All patients received ≥1×105 /kg CD22-CAR T cells .Complete remission (CR) or CR with incomplete count recovery (CRi) was achieved in 15 of 19 patients (78.9%) that could be evaluated on day 30 after infusion.Cytokine release syndrome (CRS) occurred in all patients,But most patients only experienced mild cytokine-release syndrome and neurotoxicity.In 15 CR and CRi patients, 8 patients followed by allogeneic hematopoietic cell transplantation after CD22 CAR-T, These patients remained in remission at 4 to 39.7 months after transplantation, another 7 patients did not undergo HCT, 1 relapsed at 1 months,6 of them remained in remission at 4 to 26.5 months after infusion . Among 4 NR patients, 3 died of disease progression, and 1 accepted salvage transplantation who had survived for 4.6 months.
Conclusion
CD22 CAR T-cells was highly effective in inducing remission in adult r/r B-ALL patients,transplantation followed-by CD22-CART allowed CR patients to obtain a remission of 4-39.7months.
Keyword(s): CAR-T, Lymphoplasmacytic lymphoma, Refractory